Conciseness

Mostly efficient and rich in non-obvious discipline (exposure firing rules, salt conventions, realistic-MDE calibration), but the same content recurs across sections: the delayed-exposure and always-fire traps appear in both 'The exposure log' and 'Common pitfalls', the platform-vs-warehouse factors appear in three places (intro, decision section, closing), and the 12-consideration framework restates earlier sections' guidance. This 'could be tightened' redundancy fits anchor 3 better than anchor 4's 'minor instances', though it is well above anchor 2 since none of it is generic explanation of concepts Claude already knows.

Actionability

The SQL is copy-paste ready (FARM_FINGERPRINT assignment, full Welch's t-test, dbt model with ref/var) and the statsmodels power snippet is executable, matching 'mostly executable with minor gaps'. Not anchor 5 because two Python snippets hinge on placeholder calls — 'df = warehouse.query(...)' and 'pre_period_revenue(user_id)' — that are not runnable as written; not anchor 3 because those placeholders are clearly labeled template scaffolding rather than pseudocode hiding key steps.

Workflow Clarity

The architecture section sequences the four components in data-flow order and the 12-consideration framework acts as a design checklist, with real validation checkpoints woven in ('Check the SRM before computing any metric', 'first action is to audit the exposure log and metric definitions before celebrating', pre-registered stop criteria). Not anchor 5 because these checkpoints are distributed across sections rather than an explicit validate-and-recover procedure; this is analysis, not a destructive/batch operation, so the cap at 3 does not apply.

Progressive Disclosure

All 8 referenced files exist and are one level deep (verified against the bundle: the only cross-file mention is a lateral comment pointer in metric-definitions-in-dbt.md to statistical-analysis-templates.md, not a chain). Inline content keeps the key patterns while detail is deferred with one-line descriptions per link, plus a summary reference index — matching the 'clear overview with well-signaled one-level-deep references' anchor. Not below 5: nothing that belongs in a reference is inlined at length, and navigation is easy.

Specificity

The description lists multiple specific concrete actions — 'SQL-based assignment, exposure logging discipline, metric definitions in dbt models, statistical analysis in SQL or Python, variance reduction with CUPED, sequential testing' — with named techniques (CUPED, mSPRT) and named platforms (Statsig, Optimizely), matching the comprehensive-coverage anchor. It is dense rather than padded, so the verbosity penalty does not apply.

Completeness

Both halves are explicit: 'what' is the opening capability list and operational framing ('Running experiments out of the data warehouse instead of via dedicated experiment platforms'), and 'when' is given twice with concrete trigger phrases ('Triggers on warehouse-native experimentation… Also triggers when the team is choosing between platform and warehouse, building warehouse-native experiment infrastructure, auditing one…'). This matches the score-5 example structure exactly; score 4 would require the 'when' to be merely present rather than explicit and concrete.

Trigger Term Quality

The trigger list covers natural phrases a user would actually say — 'run experiments in BigQuery', 'run experiments in Snowflake', 'dbt experiments', 'SQL t-test', 'build vs buy experimentation' — plus synonyms and specialist terms (CUPED variance reduction, exposure log, sample ratio mismatch). Not below 5: no missing common variations of consequence; not above since 5 is the anchor maximum.

Distinctiveness Conflict Risk

The niche is clearly defined — warehouse-native experimentation versus vendor platforms — and anchored by unmistakable triggers ('run experiments in BigQuery', 'dbt experiments', 'build vs buy experimentation') that no generic experimentation skill would claim. Some methodology terms (sequential testing, CUPED) are shared with general stats skills, but the opening sentence scopes everything to the warehouse context, so conflict risk is minimal; this fits the 'clear niche with distinct triggers' anchor better than the 'minor overlap risk' anchor at 4.